/*
 *    Copyright 2006-2020 the original author or authors.
 *
 *    Licensed under the Apache License, Version 2.0 (the "License");
 *    you may not use this file except in compliance with the License.
 *    You may obtain a copy of the License at
 *
 *       http://www.apache.org/licenses/LICENSE-2.0
 *
 *    Unless required by applicable law or agreed to in writing, software
 *    distributed under the License is distributed on an "AS IS" BASIS,
 *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *    See the License for the specific language governing permissions and
 *    limitations under the License.
 */
package org.mybatis.generator.internal.util;

import static org.mybatis.generator.internal.util.messages.Messages.getString;

import java.io.File;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;

import org.mybatis.generator.logging.Log;
import org.mybatis.generator.logging.LogFactory;

/**
 * This class holds methods useful for constructing custom classloaders.
 *
 * @author Jeff Butler
 *
 */
public class ClassloaderUtility {

	private static final Log LOG = LogFactory.getLog(ClassloaderUtility.class);

	/**
	 * Utility Class - No Instances.
	 */
	private ClassloaderUtility() {
	}

	public static ClassLoader getCustomClassloader(Collection<String> entries) {
		List<URL> urls = new ArrayList<>();
		File file;

		if (entries != null) {
			for (String classPathEntry : entries) {
				file = new File(classPathEntry);
				if (!file.exists()) {
					LOG.warn(getString("Warning.31", classPathEntry)); //$NON-NLS-1$
					continue;
				}

				try {
					urls.add(file.toURI().toURL());
				} catch (MalformedURLException e) {
					// this shouldn't happen, but just in case...
					throw new RuntimeException(getString("RuntimeError.9", classPathEntry)); //$NON-NLS-1$
				}
			}
		}

		ClassLoader parent = Thread.currentThread().getContextClassLoader();

		return new URLClassLoader(urls.toArray(new URL[urls.size()]), parent);
	}
}
